1. Field of the Invention
The present invention relates to a collaboration method, system, program and record medium, in which computers are peer-to-peer connected via a network, and more particularly to a collaboration method, system, program and record medium, in which collaboration is started and maintained on a network using electronic mails.
2. Description of the Related Arts
With the Internet becoming widespread, a collaboration system to collaborate on a review work at a conference, etc., sharing some object between local area-to-area is being widely used. Also, due to enhanced machine performance or network infrastructure, large capacity of data can be now exchanged on a network, that could not be handled in the past. Moreover in the future, by the IPV6 (Internet Protocol Version 6), a possibility is expected to add an IP address to even a personal computer or mobile terminal, etc. of general users.
As shown in FIG. 1, the core of conventional collaboration has been of a server/client type installing clients 202-1 through 202-3 against a server 200. On a server/client type system, a certain server 200 performs centralized control of a network. The server 200 usually holds creation, management and deletion functions of data subject to collaboration. To take part in a certain group of collaboration, only required task for the server/client type-based collaboration system is to connect a client to the well-known server. Since the server manages all users, when connection to the server completes, a newly connected user is recognized as a member of the user group under the management of the server. Because of this, a conferee has been only required to manage a relatively small number of servers by itself.
However, in the server/client type-based collaboration system, a general user himself cannot freely create a group of users to start up collaboration within that group. However, as described firstly, since possibilities are now expected that hardware condition would be advanced and an IP address would be widely added, recent years, a peer-to-peer type collaboration system as shown in FIG. 1B has been gathering attention, as another communication model lined with the server/client type. The peer-to-peer type means that each user taking part in a network as peer machines 300-1 through 300-4 is equal to another (peer), without having a specific server, and all users have capabilities to start collaboration. However, on the peer-to-peer type, as users taking part in a network would be many and unspecified persons, it is actually impossible for each user to manage the IP address of the user's connecting partner. Due to this difficulty, in order to make own IP address known to many users, after all such a method would be required to present the user's own IP address to a server which is well-known to many users, so that other users can easily know the user's own address. However, the purpose of this method is for make the IP address known to others, and nothing more, and any client intends to make communication through that server. Recognizing the IP address of the partner, the user directly connects to that IP address to begin communication. Also, as a difficult point for the peer-to-peer type to connect a network under the current network environment can be that the user of general household does not have a fixed global IP address. Generally, if the user does not have an IP address, such a method is employed that the user gains access to the ISP (Internet Service Provider) by telephone line, etc. and the ISP dynamically allocates the spooled IP addresses. Therefore, as the IP address varies whenever the user connects to the ISP, each user has to identify its partner on the network from the IP address, which may be subject to change as occasion arises. Therefore, under the current network infrastructure, a system to replace an IP address corresponding to a dynamic change of IP address is required. Also, in order to get the most out of collaboration on a network, it is important to manage scheduling or log of conference to be held. Also, especially, by automation of opening or resuming a conference, collaboration can be embodied on a network on-scheduled timetable. Moreover, to open a conference on a network, it is important to distribute data of the conference. Moreover, in order to resume the conference, it is necessary to effectively use the log of the conference. As the data or log of the conference can surely contain massive amounts of information, effective distribution method is important. Moreover, in order to ensure smooth communication as if users are really on the site, at the time of collaboration, such means as adding notes, inserting drawings, etc. are extremely effective. In the past, collaboration like adding notes or free-hand drawing had to be developed for every specific application, and development cost amounting to a considerable amount has been a problem.